The present invention relates to a technique and to apparatus for encapsulating or housing an electrical component or assembly, and more particularly, to such a technique adapted to encapsulate a horn or like electro-acoustic device.
The present invention especially pertains to the cover member of such a housing, such cover member having the facility for snapping on the horn with the use of only slight pressure, thus being amenable for firm panel mounting of such horn or other electrical component.
In order to provide an appropriate background to the subject matter of the present invention, reference may be made to U.S. Pat. No. 3,569,963 in which a complete alarm system is described and in which an alarm unit is shown as being encapsulated for mounting thereof. Particular reference may be made to FIG. 5 of the aforesaid patent in which there is shown an arrangement involving potting of a printed circuit board within a plastic housing and including a mounting ring at the front end of the housing for mounting the housing to a panel or the like.
It is a foundamental object of the present invention to improve upon the mounting and housing techniques and apparatus heretofore known for use in connection with electrical components.
Another object is to avoid the necessity for the use of screws or bolts or other complicated means for insuring the firm retention of electrical components, thereby to simplify to an extreme point the entire manufacturing operation.
A further object is to simplify the manufacturing operation by affording a press fit for the housing of electrical components which is superior to those known previously.
A further object is to provide extreme versatility in manufacturing such that a unit destined for panel mounting can be produced and this same unit can be adapted as a finished article for other uses and not necessarily only for mounting to a panel or the like.
The above and other objects are fulfilled and implemented by a major feature of the present invention which provides a cover or front end bracket as part of a housing adapted to house or encapsulate an electrical component; and further provides a back-end bracket or housing which, in similar fashion, snaps onto the horn or other electrical component. The cover and the back-end housing are complementarily formed in that they are provided with interdigitating or interfitting projections at their respective rims so that a complete encapsulation of the horn assembly can be effectuated when desired.
It is a more specific feature of the present invention that each of the fingers or projections which are spaced around the rim or periphery of each of the cover and back-end bracket is provided with a groove or channel for receiving and firmly gripping a flange-like portion at the periphery of the horn assembly. Moreover, each of the grooves, on both the cover and back-end housing, is preceded by a pear-shaped projection extending inwardly and serving to limit relative movement between the horn assembly and the two parts of the housing. However, with exertion of a reasonable amount of pressure the horn assembly will be received into the spaced grooves and will be retained therein.
A further feature of the invention resides in the provision of an integral ring formed at the inner periphery of the cover such that, when the horn assembly is moved into the spaced grooves, the front-plate or cover plate of such horn unit will abut said ring.
Another feature of the present invention resides in the provision of a unique combination of an audible and visible signal in an alarm unit, the housing for which has been already described. In accordance with such feature, an appropriate tone or audio signal of the order of 2500 Hz is supplied to the horn or transducer element of the alarm unit and this tone is interrupted at a predetermined rate by a regulated interrupter or pulsing circuit. It is specifically provided that the interrupted tone is supplied coincidently to both the horn and a suitable visual indicator, such as a light-emitting diode. However, it could be so arranged that the horn and the light-emitting diode would receive alternate half-cycles of the power supply. The light-emitting diode is arranged to project outwardly from the front of the unit at the center of a perforated plate or grill formed as part of the cover so as to permit emission of the tone signal.
The above described feature enables the alerting of supervisory personnel by visual means as well as by the tone means. The reason this is important is that in many installations a variety of conflicting tones and alarms are being emitted into a given ambient and it is extremely useful to be able to pinpoint the particular tone source; that is, to have a means further identifying which audible alarm is being given at a particular time.
Further and other objects, advantages and features of the invention will be apparent from the following description of a preferred form of the invention as seen in the accompanying drawings.